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By Richard Shea

Morris-Shea, an Alabama-based deep foundation contractor, is installing foundation piles at the sites of North America's two largest liquefied natural gas (LNG) terminals currently under construction. The contractor has crews working at Venture Global's LNG lique- faction plant in Plaquemines Parish, Louisiana, as well as constructing foundations for the Cheniere Energy Stage 3 Liquefaction Project in Corpus Christi, Texas. This work includes installing ap- proximately 27,000 DeWaal drilled, full displacement, cast-in-place concrete piles to support seven new midscale LNG trains at Cheniere's Texas ter- minal. Deep foundation installation began at Venture Global's Plaquemines facility, located approximately 30 mi (50 km) south of New Orleans, with an initial phase of 24,000 piles. Plans for the Plaquemines LNG terminal include three loading berths on the Mississippi River and four LNG containment tanks. The facility will utilize new pretreatment com- pressors, liquefaction trains and on- site gas turbine power plants to maintain an annual LNG export capacity of nearly 20 million tons (18 million tonnes) per annum. The site's LNG trains are configured in 18 blocks. The contractor is installing piles through an initial 6-20 ft (1.8-6 m) of cement mixed improved soils, which provide a safe work plat- form for equipment to operate on the extremely weak native soils. Drilling continues through soft clay in the subsurface and tips into a stiff clay or dense sand layer. Production piles are drilled to depths up to 124 ft (38 m) below ground surface. The firm is working with engi- neering, procurement and construction contractor KZJV, a Kellogg Brown & Root and Zachry joint venture, at the Louisi- ana location. The foundation team mobilized at the Plaquemines site in May 2022, to install 16, 18 and 24 in (400, 450 and 600 mm) diameter test piles to depths of 90 and 120 ft (27 and 36 m). The piling contractor returned in September 2022, to start Phase 1 of the deep foundation project, beginning installation of production piles.

Apr 1, 2023

By Joseph Mcavoy

El presente artículo señala a la excavadora terrestre más grande del mundo, como el tributo tecnológico de maquinaria moderna, el cual fue. construida por la empresa Bucyrus-Erie para la compañía Ohio Power, que forma parte del American Electric Power System, y costó 24 millones de dólares. La 4250-W, apodada "~ran Muskie", por la mina Muskingum en que trabaja, entró en servicio el año 1969, en las aderas de Cumberland, cerca de Zanesville, Ohio.

Jan 1, 1971

By Jack Elorenta

A recent forum of mine operators revealed a continuing strong interest in alternative methods of freeing rock. A Rand Corporation report lists a continuous mechanical machine that would replace drilling and blasting as a priority for mine operators. Meanwhile, mounting evidence documents a dramatic cost benefit in processing where increased blast energy is available. The reasons for this dichotomy may be due to a number of factors.

Jan 1, 2002

By D. R. Tesarik, F. M. Jones, J. B. Seymour

As part of safety and stability studies at three underground mines in the United States, researchers installed earth pressure cells and embedment strain gauges in cemented rockfill to measure stress and strain changes as mining progressed and the rockfill was loaded. Data from these instruments were used to calculate the in situ modulus of the rockfill for two of the mines. A three-dimensional numerical model of a cemented rockfill cap was validated with data from extensometers anchored in the mine roof and sill; this model was then used to estimate deformation modulus at the third mine because the earth pressure cells and embedment strain gauges recorded negligible changes. Rockfill binder used at these mines ranged from 4 to 8 per cent of the dry components by weight, the water-to-cement ratio was from 0.42 to1.0, and the largest aggregate size in the three mixes ranged from 5 to12 cm (2 to 4.7 in). The range of the calculated in situ deformation modulus values was large, but as expected, it was bracketed by modulus values for cemented tailings and roller-compacted concrete with similar cement contents and water-to-cement ratios. Dans le cadre d’études sur la sécurité et la stabilité de trois mines souterraines situées aux États-Unis, les chercheurs ont installé des palpeurs de pression des terres et des extensomètres d’encastrement dans les remblais cimentés afin de mesurer les variations relatives à l’effort et à la déformation des terrains durant l’exploitation minière et le chargement du remblai. Les données recueillies à l’aide de ces instruments ont servi au calcul du module in situ du remblai dans deux de ces mines. Le modèle numérique tridimensionnel de la semelle d’un remblai cimenté a été validé à partir des données recueillies par les extensomètres ancrés dans la voûte et dans la semelle de ces mines; ce modèle a ensuite été utilisé pour estimer le module de déformation à la troisième mine, étant donné que les palpeurs de pression des terres et les tensiomètres enfouis avaient relevés des variations négligeables. La matière d’agrégation de l’enrochement utilisée dans ces mines comportait entre 4 % et 8 % des composantes sèches par poids; le rapport eau-ciment se situait entre 0,42 et 1,0; et la taille des agrégats les plus gros dans ces trois mélanges était de 5 cm à 12 cm (2 po à 4,7 po). L’écart entre les valeurs calculées des modules de déformation in situ était grand, mais comme on s’y attendait, cet écart a été compensé par les valeurs modulaires des résidus cimentés et du béton tassé au rouleau avec des teneurs en ciment et des rapports eau-ciment semblables. Als Teil der Sicherheits- und Stabilitätsstudien an drei Bergwerken in den Vereinigten Staaten von Amerika installierten Forscher Erddruckgeber und Einbindungsdehnungsmesser in zementierter Steinschüttung, um Spannungs- und Dehnungsveränderungen während der fortlaufenden Bergarbeiten und der Belastung der Steinschüttung zu messen. Daten von diesen Instrumenten wurden dazu verwendet, das In-Situ-Modul der Steinschüt-ung für zwei Gruben zu berechnen. Ein dreidimensionales numerisches Modell einer zementierten Steinschüttungsschwelle wurde mit den Daten von den im Grubendach und in der Schwelle verankerten Extensometern validiert; dieses Modell wurde dann dazu eingesetzt, um das Deformationsmodul in der dritten Grube zu schätzen, da die Erddruckgeber und Einbindungsdehnungsmesser nur geringfügige Messabweichungen feststellten. Das in diesen Gruben verwendete Steinschüttungsbindemittel variierte zwischen vier und acht Prozent an Trockenkomponenten nach Gewicht, der Wasser-Zementfaktor betrug zwischen 0,42 und 1,0 und die größte Zuschlagstoff-größe in den drei Mischungen schwankte zwischen fünf und zwölf Zentimetern. Die Reichweite der berechneten Werte des In-Situ-Deformationsmoduls fiel etwas breit aus, aber es fand erwartungsgemäß eine Klammerung der Modulwerte zwischen den Zemen-trückständen und dem durch Walzen verdichteten Beton mit ähnlichem Zementanteil und Wasser-Zementfaktor statt.

Jan 1, 2003

By R. A. Pallanch

Sodium sulfite as a zinc retarding agent in the selective Hotation of complex lead-zinc sulfide ores was discovered by the writer in the summer of 1919 in the testing laboratory of the U. S. Smelting, Refining & Mining Co.'s gravity concentrator at Midvalc. Utah. It proved to be the first reagent to give consistently good results in the laboratory on the cornpanj's Bingham ore. In December, 1919, C. A Lemke, concentrator superintendent, recommended that a flotation unit be added to the existing gravity mill to handle the mill slimes, using sodium sulfite as the zinc depressant Owing to the poor lead and zinc markets and the unfavorable royalty schedules offered by the Minerals Separation Co., the project fell through at this time. In 1921, a number of laboratory tests were made at Midvale. on other ores, among them ore from the Sunnyside mine at Eureka, Chlo. Both sodium and calcium sulfites were used with succcss on this ore. Early in 1923, further tests were made at Eureka, shortly after the Sunnyside company had resumed operations after a two-year shutdown. AS a consequence sodium sulfite was given a trial in the mill. The results showcd sufficient improvement over previous work as to warrant continuous use of this reagent in the lead circuit Exeept for a week or so in 1926 and for several weeks in April, 1927, when sodium cyanide and zinc sulfate were given trial runs in this mill. sodium sulfite has been used ever sinee.. Sodium sulfite was chosen rather than the calcim sulfite brcauscl of its gre1ater sollubility, making it possitdr. to introduee the reagent as a solutiun. This Solution is introdueed into the Marry ball mills along with the original feed of ore,. The consumption of sodium sulfite in the Sunnyside mill varies from 1/4 to 12 lb per ton of ore, the smaller amount probably being nearer the average. In February, 1924, laboratory work at Midvale demonstratcd conclusivcly that good results could be obtaincd on the company's Bingham ore and on most of the custom ores tested by using sodiuin sulfite as the zinc depressant, xanthate as the lead enhancer in the lcad circuit, followed by copper sulfate and additional xanthate to float the zinc Sodium sulfide was used to float the iron pyrite after the lead and

Jan 1, 1928

By T. B. Counselman

PRobably the earliest concentration of iron ore in this country was carried on in the northeastern magnetite areas. Magnetic concentration was relatively simple and gave a concentrate that, after agglomeration, and in spite of beillg high in phosphorus hecause of the dry concentrating methods then in use, was satisfactory blast-furnace feed. Production from the northeastern magnetitc area languished after the discovery and development of the Lake Superior ores, where there was seemingly an unlimited tonnage of high-grade ore, first the Michigan ores, and subsequently the still larger deposits of Minnesota. For years only the higher grade, direct shipping ores of the Lake superior district were mined. Those of Michigan, and of the Vermilion Range in Minnesota, were hard ores and came principally from underground mines. The softer ores of the Mesabi came partly from underground mincs, but mostly from the enormous deposits that could be worked by open-pit methods. The costs of ore from these open-pit deposits, even with the high initial cost of stripping, were so low that the underground mines of the Mesabi could hardly compete. The so-called Old Range ores, of Michigan and of the Vermilion Range of Minnesota, were hard and lumpy, and opened UP the burden in the blast furnace, therefore making possible harder driving with greater output. Also, some of these Ores were of such grade and physical characteristics that they were suitable for charge ore in the open hearth. These ores, therefore, commanded a price premium. and could compete with the softer, finer, but cheaper, Mesabi ores. The big tonnage reserves, however, are on the Mesabi. and it is these big open-pit deposits that contitue- our stock pile of iron ore, from which we are drawing so heavily during this war period. On the western end of the Mesabi the ore was found to be high in silica, and not suitable as furnace feed. As early as 1902, attempts were made to concentrate this so-called wash ore and by 1910 the first washing plant was put into operation. The Process was very simple, consisting essentially of a sizing and washing operation, with scalping screens, logwashers and tables, which later were replaced by classificrs. Ore particles finer than I00 mesh were deliberately wasted, because these fines were undesirable in the furnace. Fortunately, these tailings were impounded, and already are being reworked. Before long some of the low-grade ores began to require more elaborate treatment than the simple washing operation and, tables having been discarded because of their low capacity, in favor of classifiers, jigs were next introduced. These were able to discard coarser pieces of tailing than classifiers. Jigs are in active use today, various improvements having been made in their design and application. Various other machines and methods of concentration have been tried from time to time, and have in turn been discarded for more improved processes., The latest and most important process that has been 38

Jan 1, 1944

By T. B. Counselman

PRobably the earliest concentration of iron ore in this country was carried on in the northeastern magnetite areas. Magnetic concentration was relatively simple and gave a concentrate that, after agglomeration, and in spite of beillg high in phosphorus hecause of the dry concentrating methods then in use, was satisfactory blast-furnace feed. Production from the northeastern magnetitc area languished after the discovery and development of the Lake Superior ores, where there was seemingly an unlimited tonnage of high-grade ore, first the Michigan ores, and subsequently the still larger deposits of Minnesota. For years only the higher grade, direct shipping ores of the Lake superior district were mined. Those of Michigan, and of the Vermilion Range in Minnesota, were hard ores and came principally from underground mines. The softer ores of the Mesabi came partly from underground mincs, but mostly from the enormous deposits that could be worked by open-pit methods. The costs of ore from these open-pit deposits, even with the high initial cost of stripping, were so low that the underground mines of the Mesabi could hardly compete. The so-called Old Range ores, of Michigan and of the Vermilion Range of Minnesota, were hard and lumpy, and opened UP the burden in the blast furnace, therefore making possible harder driving with greater output. Also, some of these Ores were of such grade and physical characteristics that they were suitable for charge ore in the open hearth. These ores, therefore, commanded a price premium. and could compete with the softer, finer, but cheaper, Mesabi ores. The big tonnage reserves, however, are on the Mesabi. and it is these big open-pit deposits that contitue- our stock pile of iron ore, from which we are drawing so heavily during this war period. On the western end of the Mesabi the ore was found to be high in silica, and not suitable as furnace feed. As early as 1902, attempts were made to concentrate this so-called wash ore and by 1910 the first washing plant was put into operation. The Process was very simple, consisting essentially of a sizing and washing operation, with scalping screens, logwashers and tables, which later were replaced by classificrs. Ore particles finer than I00 mesh were deliberately wasted, because these fines were undesirable in the furnace. Fortunately, these tailings were impounded, and already are being reworked. Before long some of the low-grade ores began to require more elaborate treatment than the simple washing operation and, tables having been discarded because of their low capacity, in favor of classifiers, jigs were next introduced. These were able to discard coarser pieces of tailing than classifiers. Jigs are in active use today, various improvements having been made in their design and application. Various other machines and methods of concentration have been tried from time to time, and have in turn been discarded for more improved processes., The latest and most important process that has been 38

Jan 1, 1944

By Rodolfo Nava

El presente texto señala las innovaciones tecnológicas en los sistemas de soporte de las minas Industrial minero México S.A. con el objetivo de incrementar los factores de seguridad y productividad. Dichos factores son: marcos de madera, marcos de acero, anclas de concha de expansión, anclas de varilla corrugada y cemento inyectado a presión, anclas de cable de acero y cemento inyectado a presión, tubos ranurados de fricción, anclas de varilla corrugada y cartuchos de resina, concreto lanzado; solo o en combinación con alguno de los tipos de anclaje anteriormente citados. En ese sentido, se considera las experiencias desarrolladas en la Unidad Taxco, con los tubos ranurados de fricción, que es el tipo de anclaje de más reciente aparición en el mercado de los Estados Unidos.

Mar 1, 1981

By L. D. Hall, S. J. Rothman

DIFFUSION coefficients of RaD (PD) and RaE (Bi) in a Bi-0.255 atomic pct Pb alloy have been measured by the methods outlined in a previous paper.' The following changes were made in the experimental procedures: the bath was made up of about 400 to 500 g Bi; and no correction was made for the volume change of bismuth on melting. The data are presented in Table I and Fig. 1. A least-squares analysis of the data yielded D = (0.120 t 0.09) exp ( -9680 + 1070/RT) D- (0.0465 0.001) exp (-8100 + 466/RT). Statistical analysis of the data indicated that the activation energies are significantly different at the 50 pct level, but not at the 75 pct level, while the D values are significantly different at the 97.5 pct level, but not at the 99 pct level. The differences are thus not as clear-cut as they were for lead. However, bismuth diffuses faster than lead in high bismuth alloys as well as in lead. The high activation energies, more than twice the value calculated from viscosities, are in good agreement with the results of Grace and Derge.' No data were obtained at higher temperatures because of gas bubble formation in the capillary. Acknowledgments This work was supported by the Office of Ordinance Research under contract DA-04-200-ORD-178. The authors thank 0. P. Vieria and M. Volpe for help in the experimental work.

Jan 1, 1957

By Miie Shields, Ed Billington

Trail blasters for the National Park Service (NPS) live and work in remote mountain terrain throughout the western states, where any support or resupply may be sporadic and ditlicult and mountain weather affects every activity. Mechanical “aids” are the pick, shovel, rock-bar, wheelbarrow, and a Pionjar or Cobra dritl. The blaster is usually faced with an extraordinary range of work, t?om delay blasts in weathered rock using driiole depths of 18” (46cm) to as little as 4” (1 Ocm), through reducing boulders and talus fields to useable tread, blasting stumps, snags and log-jams, to the explosive disintegration and casting of animal czcasses. One day he/she might provide a 500cf (14 cu meter) anchor excavation for a suspension bridge, the next day directionally fall 60” (1.5m) diameter snags in a camp area, and the following day blast a 3-foot-wide (1 meter) tread bench across a steep bedrock slope. To be effective, the blaster must design each and every blast around desired end result, crew and public safety, maximizing effective use of limited quantities of explosive, and the minimnation of environmental effects. Since almost all drillhole blasting occurs in the weathered zone of the rock, blasting is more the art than the science of judging rock density, hardness, cohesion and prefracturing, and selecting explosives, drill and delay patterns, and loading techniques responsive to those conditions. For these reasons the NPS issues its own Blaster’s License, with a basic requirement of at least 40 hours of NPS blaster training and 3 years of supervised Blaster in-Training experience. The focus of this pre-license requirement is on safety and using explosives as a precision tool, versus just “blowing things up”.

Jan 1, 2002

By Bruno César Calazans de Andrade

No processo de produção de aço o maior volume de custo está na carga metálica, que é composta pelo gusa líquido produzido nos altos fornos e a sucata metálica oriunda dos descartes de processos produtivos da indústria. Visando atingir o custo ótimo de produção, foi definida uma produção dos altos fornos menor que a média histórica da empresa, e a compra de placas no mercado como complemento para suprir a demanda da laminação. Desta forma a otimização da utilização do gusa líquido se tornou primordial para o aumento da produção de placas, redução do custo de produção da metalurgia e consequentemente redução da necessidade de compras de placas no mercado. Com este novo cenário foi necessário aumentar a utilização de sucata pesada e reduzir o tempo de preparação de caixas para garantir a carga no peso e tempo necessário para atendimento dos conversores. As ações tomadas possibilitaram a redução do gusa na carga metálica de 84% para 82% atingido o resultado proposto redução de custo e aumento de produção de placas.

Aug 17, 2017

By K. Cothern, S. Novack, D. A. Johnson, R. Borden, S. Pavlou

A procedure is presented for ranking hazardous waste sites for remedial decisions, and an example with application to mining waste sites is discussed. Typical contaminant concentrations are calculated from field data. Exposure indices that compare these measured concentrations with allowable limits are then computed. The limits are selected to protect both the health of humans (for both carcinogen and noncarcinogen effects) and the health of key organisms in the ecological food web. The additive exposure index for a site, defined as the sum of all contaminant-specific exposure indices, is then used in ranking the sites and assigning each a priority for remedial action. One key source of uncertainty in the process is the estimation of a typical site concentration from data that include values reported as "below certified reporting limit" (BCRL). This uncertainty is compounded in the additive exposure index and therefore may have a substantial effect on the assignment of remediation priority. A general approach is presented for incorporating consideration of BCRL data into uncertainty evaluation when assigning remediation priority designators to hazardous waste sites.

Jan 1, 1992

By B. J. Swenty, J. L. Hubbard, R. L. Peyton

Based on the results of the National Program of Inspection of Nonfederal Dams conducted by the US Army Corps of Engineers during 1977-1981, Missouri was found to have the highest number of "unsafe" dams in the nation. Many of the dams classified as unsafe in Missouri were tailings dams.

Jan 1, 1987

By O. P. Hood

None of the methods now in use for the transportation of materials underground is entirely free from more or less serious objection.

Jan 1, 1915

THE total crude production from the Dutch East Indies, and the British Protectorates of Sarawak and Brunei for 1932 is given in the following table: BARRELS BARRELS (42 GAL.) (42 GAL.) North Sumatra 4,226,935 Ceram 326,207 South Sumatra 13,956,157 Sarawak 2,739,650 Java 3,845,568 Brunei 1,322,725 Dutch Borneo (main island) . 9,406,733 Dutch Borneo (Island of Tara- kan) 6,579,184 Total 42,403,159 Production, which had shown a rapid increase from 1921 to 1929, has since been reduced. Exploitation drilling in the majority of the larger fields was suspended and existing production kept within predetermined limits by beaning. Most of the smaller fields were shut down entirely. The depth of producing levels varies widely in the different fields. Shallow fields with drilling depths to 500 meters (1650 ft.) are still numer-ous as well as those with depths between 500 and 1000 m. (3300 ft.). A few of the newer fields reach greater drilling depths. up to 1600 m. (5250 ft.). The deepest exploration well drilled to date (Djambi field, South Sumatra) reached a depth of 2332 m. (7650 ft.) before abandon-ment in March, 1930. The specific gravities of the various crude oils produced range between 0.65 (86.2° A.P.I.) and 0.95 (17.5° A.P.I.). The lighter crudes have a high gasoline content and fuel oils are derived from the heavier crudes, which usually are rich in paraffin.

Jan 1, 1933

By David C. Byrne

PURPOSE: Evaluate practical technological advances in level-dependent hearing protectors and inexpensive personal acoustic monitors. RESEARCH SUMMARY: The results of previous NIOSH research show that miners develop hearing loss much more quickly than nonoccupationally noise-exposed individuals and that miners experience a greater severity of hearing loss than would be expected for nonoccupational noise-exposed persons of the same age and gender. Using hearing thresholds at 4,000 Hz as an indicator, coal miners experience hearing loss 2.5 to 3 times greater than would be expected for persons not exposed to occupational noise. At age 50, 90% of coal miners and 49% of metal/nonmetal miners were found to have a hearing impairment. In comparison, only 9% of a nonoccupationally exposed control group had a hearing impairment at age 50. There are numerous barriers to the prevention of hearing loss among miners. In an effort to overcome some of these obstacles, this work was initiated to evaluate practical technological advances in level-dependent hearing protectors and inexpensive personal acoustic monitors. Experiments will involve analysis of this new technology under both laboratory and field conditions. Laboratory components will consist of controlled studies using an anthropometrically correct test fixture as well as human subjects to evaluate the adequacy/effectiveness of various hearing protective devices. Electroacoustical performance testing of new noise monitors will also be conducted in a laboratory setting. Subsequent field studies will determine the actual usefulness and practicality of the personal protective/monitoring equipment as used in different mining situations. It is anticipated that increased on-the-spot awareness of hazardous noise levels and the availability of better-suited hearing protectors will provide a degree of protection beyond what is currently attained in different mining environments. Therefore, the intent of this project is to identify and adapt new acoustical technologies and products that have a direct application to individual mine workers. With increased knowledge of these technological advances, a greater demand for similar devices will likely occur, which, in turn, will lead to a better understanding and awareness of hearing loss prevention methods throughout the mining community. The ultimate goal is for widespread integration of useful hearing loss prevention products and devices into the daily routines of miners

Jan 2, 2000

By George S. W. Cumpston

El presente texto describe los factores que intervienen en la economía de la molienda con bolas, considerando la carga y calidades de las mismas. Para determinar cuáles son los factores en el estudio económico, es necesario conocer las cuatro calidades básicas de las bolas de las moliendas: las bolas de aleación de acero, forjadas y con tratamiento térmico, las bolas de acero al carbono forjadas y con tratamiento térmico, las bolas de aleación de acero fundido y las bolas de fierro fundido. Los productos fundidos generalmente no son tratados térmicamente y las bolas de fierro fundido son un producto de bajo precio y más ordinario. En este sentido, una bola tratada térmicamente sea en aleación de acero o de acero al carbono, tendrá una estructura granular más fina que las de los productos fundidos. Para fijar la economía de un tipo de bola, se utilizan dos formas de investigación: la prueba de bolas marcadas y la de resultados de producción, estableciendo esta última como la más exacta, aunque requiera molinos duplicados para medir su producción. Luego, se procede a experimentar con diferentes tipos de bolas -a través del costo de transporte y manejo requeridos para moler una tonelada de mineral- y asi determinar cuál es la bola más económica para cada operación. Posteriormente se evalúa la facilidad de la molienda y se delimita la carga de bolas que se aproxime mejor a la carga balanceada.

Jul 20, 1960

Circuit alterations and adoption of more compact items of equipment have made it possible to increase the capacity of the King Island Scheelite concentrator, both with regard to head grade and feed tonnage, while at the same time increasing total recovery and reducing maintenance costs. The present operation is described, with particular emphasis being placed on alterations made during the last two years to achieve capacity Goals.

Jan 1, 1977

By D. Kok

A challenge in mine planning is the optimal allocation of resources to the appropriate workplaces within the shift cycle (labour, equipment type, and other resources) in order to carry out the shift cycle activities, achieve planned production targets, and ultimately maximize production within all infrastructure constraints. Generally, detailed mine planning is done on a monthly basis at a workplace level in order to determine the production targets. The production supervisor, mine overseer, or equivalent production manager must then make the appropriate resource allocation trade-off decisions on a daily basis per shift to try and deliver to the plan and required production target. Due to the complexity and number of permutations of possible resource allocation decisions, it is impossible for a human brain to make the appropriate and optimal allocation decisions that will result in achieving the maximum or target production. These allocation decision permutations must deal with the current status of workplaces (availability, position in the cycle etc.), the status of equipment availability (available, planned maintenance, or breakdown etc.), distance between the workplaces (traveling time of equipment between workplaces, etc.) and equipment type required for that shift cycle activity. All these factors need to be taken into account in resource allocation to plan for the shift, and even during the shift if a major piece of equipment becomes unavailable or a workplace activity is not progressing as planned. This paper is a case study on how an optimization algorithm can be used to create a production planning system for optimization of resource allocation in a mechanized underground platinum operation. A business case for optimal allocation of resources is demonstrated and compared to the current manual planned allocation.

Jan 1, 2012

By D. F. Toner, P. E. Gage, D. J. Mack

MUCH work has been done on the decomposition of the p phase at the eutectoid composition, 11.9 pct Al, in the Cu-A1 system by Smith and Lind-lief,' Mack,' Klier and Grymko,3 Haynes,4 and others. In all of the mechanisms proposed by these workers for the decomposition of the ß phase, it was stated that the a phase must precipitate rich in aluminum with respect to the equilibrium composition of 9.4 pct A1 at 565°C. To check this hypothesis, it was necessary to have a master curve relating equilibrium aluminum content of a to lattice parameters of a. A number '' binary Cu-Al alloys of increasing amounts of aluminum were prepared by Ampco Metal Inc. These alloys, received as-cast, were given a 30 pct reduction of area by hot-working and then annealed at 900°C for homogenization and slowly cooled in the

Jan 1, 1956